Diffuser for the outlets of air ducts



Jan. 6, 1942. cQN. o'DAY' DIFFUSER FOR THE OUTLETS OF AIR DUCTS Filed Oct. 23, 1939 Patented Jan. `6, 1942 UNITED STATES PATENT OFFICE mrrvssn Foa 'rmi oU'rLa'rs or Am Doors Application October 23, 1939, Serial No. 300,889

Claims.

This invention relates to diifusers particularly designed for the room outlets of ceiling ducts in air conditioning systems.

The general object of the invention is to provide a diuser which shall answer the problems that attend the admission of conditioned air to rooms by way of outlets from overhead conduits. Some of these problems are as follows:

1. When there are two or more hot or cold air outlets from a duct, it is generally necessary to employ some means to regulate the amount of air discharged from each outlet. to ensure equal or desired proportionate distribution of the air. It is, therefore, becoming more generally recognized that some form of. damper is required behind ceiiing outlets, in order to properly regulate the quantity of air discharged from the plural outlets of a duct system to proportionately distribute the conditioned air.

However, in order to quickly mix the incoming hot or cold air with the room air, turbulence is (a) To provide a ceiling diffuser in connection with the duct outlet, so constructed that the velocity. of the introduced conditioned air shall be at a maximum at the outlet or outlets of the diffuser. 1

(b) To provide an adjustable diffuser by means of which the diffuser can be set,` after installation, to increase or decrease the velocity or/and volume of the introduced air, to obtain the desired condition of the room' air;

(c) To provide a diffuser in which the velocity of the discharged air can be increased or decreased, when a damper is used in the outlet behind the diffuser;

(d) To provide a diffuser in which the conditioned al1` is introduced with relativelyvhigh velocity in divergent curtains which create a low pressure area therebetween, for the purpose of introducing turbulence in said area which is esnecessary, andthe amount of turbulence varies directly with the velocity of the introduced air.

Consequently, when mere dampers are relied upon to effect equal or proportionate distribution of the air to the several outlets, the one which is the more throttled by the damper will have the velocity of the incoming air reduced. This change in velocity at the outlet may be sufficient to prevent proper turbulence and interfere with the mixing of the incoming air with the room air to an extent sufficient to cause drafts and cold spots in. the space served.

2. The volume of the conditioned air admitted in a unit of time by way of the duct outlets is another important factor in the proper temperature equalization in a given space. This is also a factor of the velocity at which the air enters the room or space.

3. The required volume of introduced conditioned air, to give the desired freshness or temperature to the room, depends upon many factors, such as the temperature differential between the conditioned air and the room temperature, the occupancy of the room, etc.; so that it is readily seen that there are many chances of error in sizing a ceiling diffuser, to produce the desired condition of the room air, unless the diffuser is of such construction that the velocity as well as the volume of the conditioned air issuing from an outlet can be adjustably increased or decreased after the diffuser is installed.

With the solution of the above and other problems in view, the present invention hasfor its more specific objects:

sential to the rapid mixing of the introduced air with the air of the room.

Another object of the invention is the provision of a diffuser including a ceiling plate having a surrounding flange against which the introduced air or'a portion thereof impinges, nullifying its velocity, or a part thereof, to prevent excessive air movement or draft, and deflecting the air downward to any desired extent according to the depth of the flange or the diameter of the ceiling plate.

Still another object of the invention is the provision of a diffuser having annular outlets or nozzles, one of which may be adjusted in width so as to vary the velocity and volume of the air discharged therefrom.

A further object of the invention is to provide a diffuser of the type ldescribed which can be shipped knocked down, and assembled on the job.

Other objects of the invention will appear as the following description of a preferred and practical embodiment thereof proceeds.

In the drawing which accompanies and forms a part of the following specification, and throughout the several figures of which the same characters of reference have been employed to designate identical parts:

Figure 1 is a vertical section through a diffuser, embodying the principles of the present invention and the adjacent portions of the conduit of the outlet wall and ceiling.;

Figure 2is a plan view, part being broken away;

Figure 3 is a view similar to that of Figure l,

showing the diffuser installed without the employment of the ceiling plate; and

Figure 4 is a vertical section, part being broken away, of a modified form of the invention.

Referring now in detail to the several figures. the numeral I represents the wall of a conduit such as is employed for the conveyance of warm or cold air, and which opens into a room space by means of outlets, the wall of one of said outlets being indicated by the reference character 2. 'Ihe ceiling structure and which is not'l important to the present invention, is represented in general by the reference character 3, the conduit I being shown lying in a horizontal position above the ceiling, and the outletspenetrating the ceiling.

The diffuser comprises a plurality of hangers 4. The number of these is variable, three or four being suggested as the preferable number, the hangers being arranged at equal angular intervals about the circumference of the outlet. The hangers consist of resilient metal rods or strips, the upper ends 5 of which are provided with longitudinal slots 6, for receiving a screw 1, which is screwed through the side wall of the outlet and into the ceiling structure, securing the hangers in place. v

The hangers are bentinwardly and then outwardly so as, taken together, to form a spider structure having a narrow neck at the angles 8. 'Ihe lower or free ends of the hangers are preferably bent up to form a hook or bead 9, preferably of circular cross-section.

The diffuser includes a bailie plate I0 which, as shown, is of annular shape, although the exact shape is immaterial to the invention. The baille plate I0 is formed with a large opening II forming an air passage. This opening is of such a size as to iit around the neck of thel spider constituted by the several hangers. By virtue of the resilience of the hangers the lower flaring portions I2 may be squeezed together sufilciently to enable the baille plate I0 to be telescoped thereupon up to the plane of the angles 8. When the hangers are released they expand against the edge of the opening II, holding the baille plate Ill firmly in place. It will be noted that for the sake of rigidity as well as finish, the baille plate I0 is provided with a reinforcing bead along its inner and outer edges.

A central baille plate I3 is provided which, as shown, is circular in shape, although the shape may be other than circular and still be within the purview of the invention. The outer edge of the central baille plate I3 is formed with a reinforcing bead of such size and shape as to fit within the hooks 9 at the ends of the hangers.r The central baiiie plate I3 is of such size as to require the separating of the lower portions I 2 of the hangers, in order to iit the central baffle plate into place, and therefore the central baiile plate may be regarded as a key for holding the various parts of the diffuser in rigid assembly. It is obvious from the above description that the diffuser is shipped in knocked-down condition and is assembled on the job. The saving in transportion thus materially reduces the cost of its installation.

The diiusers shown in Figures l, 3 and 4 are substantially the same in structure, and as above described. The difference between these figures is that in Figure 1 a ceiling plate I4 is provided, which is set into the ceiling, having a peripheral downwardly extending flange I5. In Figure 1 the plaster is molded into a flange I6 which enconduits.

compasses the flange I5 and extends to a distance below said flange.

In Figure 3 there is no ceiling plate, and in Figure 4 the ceiling plate I1 rests against the ceiling with the depending flange I8 and without the benefit of the plaster dam.

Referring once again to Figure 1, it will be noted that the bale plate I0 has an inner band or zone I9, which slopes in a downward and outer direction, and that the central baille plate I3 has a peripheral zone 20 which slopes downwardly and outwardly, the central baffle plate underlying the opening II and underlapping the zone I3 of the baille plate I Il. The two baille plates cooperate, in the zones I9 and 20, to form a nozzle 23 the cross-section of which throughout its circumferential extent is convergent outwardly, being nar rowest at its outlet. This increases the velocity of the air at the point at which it is introduced into the room body of air.

It will be noted also, that the baille plate I0 is provided with a circumferential band or zone 2| extending upwardly toward the ceiling plate in Figures 1 and fi, and toward the ceiling itself in Figure 3, forming with the surface which it approaches, a surrounding nozzle 22, the crosssection of which is outwardly convergent. This also iglcreases the velocity of the air as it enters the rom. This is a most important feature of the invention, for it is necessary that the air` jets have a relatively high velocity upon entering the room atmosphere to produce the necessary turbulence forquick mixing `and equalization of temperature. The dotted lines a and b in Figures l, 3 and 4, indicate that preferably the direction of the nozzles is such as to cause the air to be introduced in the form of divergent jets or curtains.

venting drafts and cold or hot spots in the room atmosphere. The same eifectis produced by the flange I8 in Figure 4.

As has been stated in connection with the relating of the objects of the invention, it is impossible to forecast precisely the conditions which will determine the proper sizing of the diffuser so that some means of adjustment is necessary. This is provided by the screw and slot connections between the hangers 4 and the side walls of the outlet 2. If an increase in velocity is required, the screws may be loosened and the entire diffuser pushed upwardly, bringing the baille plate I0 closer to the ceiling, reducing the size of the nozzle 22. and increasing the velocity of the air issuing from said nozzle. This adjustment is required, particularly when there are a plurality of outlets opening from the duct or conduit I, and Where dampers are used in the outlets back of the 'diffusers for producing equal or proportionate distribution of air to the several If one damper is closed more than another it means an initial relatively low velocity of the air entering the outlet so restricted. This velocity, therefore, is boosted by adjusting the diffuser so as to bring it closer to the ceiling.

Sometimes it may be found necessary t reduce the velocity according to room conditions,

This creates an area of lowI pressure :r between them, drawing the air together which is easily done by loosening the screws 1, and drawing the difluser farther away from the ceiling so as to increase the outlet area. of the nozzle 22.

In all of these forms of the invention it will be observed that the nozzle 23 formed between the baille plate I and the central baille plate i3 is not adjustable.

For very low-ceilings it may be found necessary to adjust the diffuser so that the baille plate I0 touches the ceiling or ceiling plate. This, of course, reduces the effective operation of the diffuser to the single nozzle 23.

In Figure 4 is shown a modified form of the invention in which the nozzle 22 may be employed as the air inlet and the nozzle 23 as the air outlet, the latter being connected to an exhaust pipe 24. l

While I have in the above description disclosed what I believe to be a preferred and practical embodiment of the invention, it will be understood to those skilled in the art that various changes in shape, arrangement of parts, and details of construction maybe employed without transcending the scope of the invention whic is defined in the appended claims. I

v What I claim as my invention is:

1. Diffuser for the room outlets of air ducts comprising in combination with the wall of the outlet and the adjacent ceiling wall, hangers extending from spaced points' downwardly from said outlet, a baille plate supported by intermediate parts of said hangers arranged transversely of the direction of air flow through said outlet, encompassing an air passage communicating with said outlet, said baille plate comprising a downwardly inclined inner band bounding said air passage and an upwardly inclined peripheral band convergent toward the ceiling, forming therewith a peripheral nozzle of converging crosssectlon, increasing the velocity of air discharging through said nozzle, and a centralbaiiie plate supported by the lower parts of said hangers, underlying said air passage and underlapping the downwardly inclined band of said encompassing baille plate', the lapping portions of said baille plates being cooperably outwardly convergent, forming a peripheral nozzle for increasing the velocity of the air discharged between said baille plates.

2. Diffuser for the room outlets of air ducts comprising in combination with the wall of the outlet and the adjacent ceiling wall, hangers extending from spaced points downwardly from said outlet, a baille plate supported by intermediate parts ofA said hangers arranged transversely of the direction of air flow through said outlet, encompassing an air passage communicating with said outlet, said baille plate comprising a downwardly inclined inner band bounding said air passage and an upwardly inclined peripheral band convergent toward the ceiling, forming therewith a peripheral nozzle of converging cross-section, increasing the velocity of air discharging through said nozzle, and a central baille plate supported by the lower parts of said hangers, underlying said air passage and underlapping thedownwardly inclined band of said encompassing baille plate, the lapping portions of said baille plates being cooperably outwardly and downwardly convergent, forming a peripheral nozzle for increasing the velocity 0f the air discharging between said bailles.

3. D'iiuser as claimed in claim l, said hangers being adjustably supported to bring said encompassing baille plate closer to or farther from the ceiling wall.

4. Diffuser as claimed in claim 1, said hangers being adjustably secured to the wall of said duct outlet by a screw and slot connection, permitting said encompassing baille plate to be brought closer to orA farther from the ceiling wall.

5. Combination as claimed in claim 1, including means forming a` flange depending from said ceiling wall into the ,path of air discharged from the first mentioned peripheral nozzle.

6. Combination as `claimed in claim 1, including a ceiling plate having a downwardly directed vflange extending into the path of air discharged from the first mentioned nozzle.

'1. Diffuser for the room outlets of air ducts comprising in combination with the wall of the outlet and the adjacent ceiling wall, hangers extending from spaced points downwardly from said outlet, an annular baille plate supported by intermediate parts of said hangers arranged transversely of the direction of air flow through said outlet, said baille plate comprising a downwardly inclined inner band bounding the opening in said annular baille plate, and an upwardly inclined peripheral band convergent toward the ceiling wall, forming therewith a peripheral nozzle of convergent cross-section, increasing the velocity of the air discharging through said nozzle, and a central baille plate supported by the lower parts of said hangers, underlying the opening in said annular baille plate and underlapping the downwardly inclined band of said baille plate, the lapping portions of said baille plates being cooperably outwardly convergent forming a peripheral nozzle for increasing the velocity of the air discharging between said baille plates.

8. Combination as claimed in claim l, the relative angle of deflection between said nozzles being such as to produce divergent curtains of air in the room, forming between them low pressure areas which create the turbulence essential for rapid mixing.

9. Diffuser for the room outlets of air ducts comprising a plurality of resilient hangers adapted to be secured in spaced angular relation to the surrounding wall of an air outlet, said hangers together constituting a baffle plate sup'- porting spider, said hangers being bent angularly inward at an intermediatepoint and having intumed lower ends, the troughs of said angles together, forming an intermediate narrow neck affording a seat for an annular baille plate, which is seated by drawing together the ends of the hangers and passing them vthrough the hole in the annular baille plate, and a base baille plate somewhat larger than the base defined between the free ends of said hangers, seated on the inturned ends of said hangers and'maintaining the lower portions of said hangers in spread relation under tension.

10. Diffuser as claimed in claim 9, the upper ends of said hangers being longitudinally slotted, providing longitudinal adjustment for said diffuser in cooperation with means passing through said slots for securing said diffuser to the wall 

